Brake device

ABSTRACT

Wheel structure having an outer tire region of flexible material hollowed to define an annular dead end fluid passage containing entrapped fluid.

United States Patent Wochner Mar. 14, 1972 [54] BRAKE DEVICE [56]References ited [72] Inventor: Joseph J. Wochner, Pontiac, lll. UNITEDSTATES PATENTS [73] Assignee: lnterlake Steel Corporation, Chicago, lll.2,833,347 5/1958 Terry 1 88/298 X 3,314,514 4/1967 l'lundhausen et al......l93/35 A [221 Wed: June 1970 3,078,966 2/1963 Thomas 88/298 1 A l.N 46 13 l 1 PP Primary Examiner--Evon C. Blunk Assistant Examiner-W.Scott Carson [52] us. Cl. ..193/3s A, 188/290 Attorney-William Porcelli[51] Int. Cl ..B65g 13/00, 865g 13/075 58 1 Field of Search ..193/35 A;188/266, 272, 290, [571 ABSTRACT 188/293 Wheel structure having an outertire region of flexible material hollowed to define an annular dead endfluid passage containing entrapped fluid.

4 Claims, 8 Drawing Figures BRAKE DEVICE BACKGROUND OF THE INVENTION Thepresent invention generally relates to the art of braking or snubbingdevices, and more particularly, relates to a snubbing device havingparticular application in gravity flow conveyors for retarding thevelocity of objects traveling along such conveyors.

A braking device for retarding the velocity of gravity conveyed objectsis shown and described in U.S. Pat. No. 3,473,642 of W. C. Lorden etal., which is assigned to the assignee of the present invention, and thedisclosure of which to the extent not inconsistent herewith isspecifically incorporated herein by this reference.

Briefly, the device shown in the above copending application includes aroller mounted so as to be rotated by an object moving along theconveyor. A controlled drag against rotation of the roller, and hence,controlled braking force on the object being conveyed is accomplished byconnecting the roller through a crank to reciprocally drive a pistonwhich is slidably guided in a cylinder containing fluid. The piston isprovided with a small orifice through which the fluid is metered fromone side of the piston to the other during reciprocation thereof, theresistance of the orifice to through-flow of the fluid acting to retardrotation of the roller, and thereby brake the moving object.

A desirable featureof the above-described braking device is that itprovides a braking force which increases in proportion to the force andspeed with which a load traveling on a conveyor contacts it. A seconddesirable feature is that it is functionally operative in two directionsof travel of a load operating on it. There remains, however, a need fora braking device having the above desirable features but which is ofsimpler and less expensive construction.

SUMMARY OF THE INVENTION In accordance with the present invention, abraking device for retarding the movement of an object includes a bodyof flexible material having an elongated fluid passage containingentrapped fluid. A flow restricting orifice is produced in the passageby virtue of localized squeezing engagement of the body by means whichfurther produces'fluid-throttling travel of the orifice relative to thefluid in the passage upon movement of the object, the above means beingengageable in'retarding relation with the object so that the resistanceof the orifice to through-flow of the entrapped fluid acts to brake themovement ofthe object. v

In the form illustrated herein, the above means comprise a pair ofwheels and the body of flexible material is mounted in tirelikefashion'on one of the wheels with the passage annularly encircling thewheel. The wheels are rotatable in a common plane and mounted so thatthe tirelike body is squeezed therebetween (thus producing the orifice).

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of theinvention will be had upon reference to the detailed description tofollow and to the accompanying drawings in which:

FIG. 1 shows a partial perspective view of a gravity conveyor embodyingbraking devices made in accordance with the present invention;

FIG. 2 shows a top plan view of a braking device indicate in use in FIG.1;

FIG. 3 is a sectional view taken, as indicated, along the line 3-3 ofFIG. 2;

FIG. 3A is a sectional view taken, as indicated, along the line 3A--3Aof FIG. 2;

FIG. 3B is a sectional view taken, as indicated, along the line 38-38 ofFIG. 2; FIG. 4 shows a side-elevational view of the snubber wheel inaccordance with the present invention;

FIG. 5 shows a sectional view of the snubber wheel taken, as indicated,along the line 5-5 of FIG. 4; and

FIG. 6 shows a side-elevational view illustrating the condition of thesnubber wheel when the tire is squeezed between the roller and wheel.

DETAILED DESCRIPTION As more fully described below, the braking deviceof the present invention utilizes the known technique of causing captivefluid to be metered through an orifice, the relative size of whichdetermines the magnitude of braking force.

Essentially, the braking device of the present invention for retardingthe movement of an object includes a body of flexible material that hasan elongated dead-end flow passage containing entrapped fluid. Meanssqueeze the body to produce a fluid-restricting orifice within thepassage, the means being responsive to movement of the object inretarding relation thereto to produce fluid-throttling travel of theorifice relative to the fluid in the passage, the resistance of theorifice to metering or through-flow of the entrapped fluid acting tobrake the movement of the object.

As described more fully below, in the illustrated arrangement, theabove-mentioned means comprise a pair of wheels 7 and 32, the body offlexible material comprising an outer tirelike region 34 of wheel 32(FIGS. 4 to 6). Wheels 7 and 32 are mounted to rotate in a common planeabout axes which are spaced a distance so that the tire region 34 ofwheel 32 is squeezed between wheels 7 and 32 so as to constrict the tireregion and form an orifice 52 in the passage 36 that annularly encircleswheel 32. Upon being urged to rotate, wheel 7 in turn drivingly rotatestire 34 and wheel 32, thereby forcing the orifice 52 to move relative tothe entrapped fluid in the passage 36. The ensuing resistance of theorifice 52 to through-flow of the fluid acts to resist rotation of wheel7, the amount of resistance being a function of the relative size of theorifice which is determined by the spacing of the axes of wheels 7 and30.

For purposes of complete illustrative disclosure, the braking device isshown herein as it may be incorporated for con trolling the speed of anobject or load being conveyed along a gravity conveyor. 1

As particularly indicated in FIG. 1, the gravity conveyor 1 is mountedwith a slope which would ordinarily cause the object.

or load 2 to move down the conveyor 1 in the direction of the arrow 3.The conveyor'l is of conventional construction having guide rails 4arranged in pairs withfreely rotatable rollers 5 mounted between thepairs of rails 4 with the upper portions of the rollers projectingslightly above the upper surface of the rails4. The conveyor is shownina combination of three roller widths, but it can be of any desired widthincluding rollersof suitable lengths to accommodate the width desired.

Unless arrested or retarded in movement, the load 2 is free toaccelerate down the conveyor 1. Oftentimes, the acceleration causesexcessive speed resulting in damaging impacts to the load upon its beingstopped intermediate or at the end of the conveyor. In order to retardthis acceleration and reduce the speed of the load 2 to a desired level,retarder devices 6 incorporating the invention are suitably positionedat desired intervals along the length of the conveyor 1. Although onlytwo retarder devices 6 are indicated on the length of the conveyor 1shown, the number of retarder devices 6 required depends upon the lengthof the conveyor, its slope, the weight of the loads 2 and the spacing ofthe braking devices 6 from each other.

Each of the retarder devices 6 is provided with a rubber rimmed wheel orbraking roller 7 which ordinarily projects slightly above'the level ofthe rollers 5 of the conveyor so that a load 2 rolling down the conveyorwill have its lower surface contacting these brake rollers 7 and causetheir rotation.

With reference to FIGS. 2 and 3, the basic frame of the retarder devices6 consists of two sideplates 8 and 9 which extend parallel to each otherand are spaced in this parallel position by means of spacer sleeves 10extending transversely of the sideplates 8 and 9. Certain of the spacersleeves 10 are held assembled to the sideplates 8 and 9 by means of boltfasteners 11 extending through the spacer sleeves l and suitableopenings in the sideplates 8 and 9. In addition, two of the spacers aremounted on shafts 12 and 13 which are used to mount the braking devices6 on the conveyor 1. The shaft 12 extends through slots S (FIG. 3B) inthe sideplates 8 and 9, respectively, and beyond the lateral margins ofthese sideplates 8 and 9. Additional spacer sleeves 14 are provided onthese projecting ends of the shaft 12, and these ends extend throughopenings in the rails 4 and are secured in place by means of threadedfasteners 15 secured on their threaded ends. The threaded fasteners 15are secured on the shaft 12 in a manner to provide a looseness betweenthe spacer sleeves 14 and 10 as that the sideplates 8 and 9, along withthe mechanism attached thereto, can pivot on the shaft 12 to raiseopenings in theseadjustment plates 16 and 17 so that the adjustmentplates 16 and 17 cannot shift transversely relative to the shaft 12.Further, the shaft 12, once positioned in rails 4 is likewise preventedfrom shifting relative to the rails 4. If it is necessary to adjust therelative height of the brake roller 7, it is necessary to move thesideplates 8 and 9 of the retarder device 6 up or down relative to theshaft 12 along the slots S until the desired position is reached. Duringthis movement, the sideplates 8 and 9 must likewise shift relative tothe adjustment plates 16 and 17 because the shaftsare in a fixedposition relative to these adjustment plates 16 and 17. in order toaccommodate this motion, the bolt fasteners 11 are loosened so that theadjustment plates 16 and 17 are free to shift relative to the sideplates8 and 9 as they are guided in slotted openings 19 and 20 (FIG. 3B). Whenthe proper position is reached, the bolt fasteners 11 are tightened tofix the positions of the adjustment plates 16 and 17 relative to thesideplates 8 and 9.

At the end ofthe retarder device 6 supported by the shaft 13, the shaft13 extends through slotted openings S (FIG. 3A) which permit relativemovement up and down of the sideplates 8 and 9 relative to the shaft 13as they pivot on the shaft 12. One end 21 of a tension spring 22 issecured around the spacer 10 on shaft 13 and its other end 23 issecuredaround the spacer sleeves 10 on one of the bolt fasteners 11.

The normal position of the retarder device 6 is one whereby the slots Shave their ends clear of the shaft 13 so that there can be relativemovement in both directions of the retarder device 6 relative to theshaft 13. As a load 2 comes down the conveyor 1, enough free movementagainst the pressure of the spring 22 must be provided so that the upperperiphery of the brake roller 7 can lower slightly to properly contactthe lower surface of the load 2. The slotted openings 8' should be longenough so that there is sufficient travel in both directions that thebrake roller 7 can return to its raised position after the load 2 haspassed over it. The force of the spring 22 must be sufficient tostrongly urge the brake roller 7 against the undersurface of the load 2and thereby minimize slippage between the brake roller 7 and the load 2.

To provide relative continuity of support along the conveyor 1,auxiliary rollers 25 are suitably journaled on shafts 26 and theserollers 25 are positioned at levels approximately equal to the levels ofthe rollers 5 of the conveyor 1,

The brake roller 7 is mounted on a shaft 27 which is suitably journaledfor rotation in bearings 28 secured to the sideplates 8 and 9. To applya braking force on the load being conveyed, wheel structure comprising awheel 32 having an outer tire portion 34 is mounted for rotation belowthe wheel or brake roller 7. The tire portion 34 has an interiordead-end flow passage 36 which annularly encircles the wheel 32 andterminates at opposite sides 38, 40 of a solid or dammed region 42 ofthe tire 34. The flow passage 36 is completely filled with a suitablehydraulic fluid, such fluid being introduced through a suitable inputport 44 at one side of the dammed region. A

suitable air escape port 46 at the opposite end of the passage 36facilitates fluid fill.

As will become clear, the above wheel structure performs a snubbingfunction and will be referred to hereinafter as snubber wheel 30.

The snubber wheel is mounted on a shaft 48 which is suitably journaledin bearings 50 that are by suitable means adjustably secured to thesideplates 8 and 9 so that the distance 1 (see FIG. 6) between the axesof rotation of the roller7 and wheel32 can be varied.

As best shown in FIG. 6, the distance 1 is such that the roller 7 andthe wheel 32 cooperate to squeeze the tire 34 in between. This causesthe passage 36 to constrict and thereby define a flow-retarding orifice52.

Upon passage of an object 2 being conveyed, the roller 7 will be causedto rotate and, because. of the frictional contact between the roller 7and the snubber wheel 30, corresponding rotation of the latter will beeffected.

it will be noted-that as the roller 7 and snubber wheel rotate, theorifice'52 will be caused'to move lengthwise rela- 1 tive to the fluidin the passage 36. Such results in a fluid pressure buildup in theregion of the chamber forward to the direction of travel of the orificecaused by resistance of the orifice to through-flow of the fluid whichresists relative movement of the orifice and, hence, rotation of theroller 7. The resistance to rotation varies according to the size of theorifice formed so that by adjusting the distance 1, proper snubbingaction can be obtained.

The outer periphery or rim 32 of the wheel 32 is shown having a radiallyinwardly projecting recess 54 in theregion of the solid or dammedportion 42 to accommodate inward flexing of the tire 34 in the region ofthe dammed portion. This permits for unimpeded 360 rotation of theroller 7 and snubber wheel 30.

In the preferred embodiment shown herein, the tire 34 is fabricated byseaming together (see FIG. 5) a pair of molded tire sections that areveach channel-shaped in cross section. The tire is then cemented to thewheel 32.

' While the snubber wheel 30 is illustrated herein as having a Iconveying objects, a braking device for retarding the movement of anobject traveling along said conveyor comprising, a body of flexiblematerial having an elongated dead-end flow passage containing entrappedfluid, and means'in localized squeezing engagement with said body forproducing a fluidrestricting orifice within said passage, said meansbeing movably responsive to movement of the object in retarding relationthereto to produce fluid-throttling travel of said orifice relative tothe fluid in said passage, whereby resistance of said orifice tothrough-flow of the entrapped fluid acts to brake the movement of theobject along the conveyor and wherein said means comprise a pair ofwheels, one of said wheels mounting said body in tirelike fashion inpinched rolling engagement with the other of said wheel structures.

2. A braking device in accordance with claim 1, wherein said meansincludes a pair of wheels mounted to rotate in a common plane aboutparallel spaced axes, said body being mounted in tirelike fashion on oneof said wheels in pinched greater uniformity in snubbing I 3. A brakingdevice in accordance with claim 1 wherein said means includes a pair ofwheels mounted to rotate in a common plane about parallel spaced axes,one of said wheels being frictionally engageable with the object so asto be drivingly rotated thereby, said body being mounted in tirelikefashion on one of said wheels in pinched engagement between said wheelswith said passage annularly encircling said one of said wheels, wherebysaid travel of said orifice is effected through rotation of said wheels.

4. in a gravity conveyor, snubber mechanism for controlling the speed ofan object being conveyed along the conveyor, said snubber mechanismcomprising, a pair of wheel structures mounted to rotate insubstantially nonslip rolling engagement about a pair of parallel spacedaxes with one of said wheel structures being in intercepting relation tothe travel path of movement of the object being conveyed so as to berotated upon passage of the object, the other of said wheel structureshaving an outer tire region of flexible material hollowed to define adead-end flow passage annularly encircling said other of said wheelstructures and containing entrapped fluid, the distance between saidaxes being less than the sum of the radii of said wheel structures toeffect localized pinching of the tire region and constriction of acorresponding region of the flow passage to provide a fluid flowrestricting orifice within said passage whereby rotation of said wheelstructures produces travel of said orifice in fluid throttling relationrelative to the fluid in said passage, the resistance of the orifice tothrough-flow of the entrapped fluid acting in opposition to saidrotation to produce braking action by said one of said wheel structureson the object when the object is in contact therewith and being conveyedalong the conveyor.

1. In combination with an elongated conveyor surface for conveyingobjects, a braking device for retarding the movement of an objecttraveling along said conveyor comprising, a body of flexible materialhaving an elongated dead-end flow passage containing entrapped fluid,and means in localized squeezing engagement with said body for producinga fluid-restricting orifice within said passage, said means beingmovably responsive to movement of the object in retarding relaTionthereto to produce fluid-throttling travel of said orifice relative tothe fluid in said passage, whereby resistance of said orifice tothrough-flow of the entrapped fluid acts to brake the movement of theobject along the conveyor and wherein said means comprise a pair ofwheels, one of said wheels mounting said body in tirelike fashion inpinched rolling engagement with the other of said wheel structures.
 2. Abraking device in accordance with claim 1, wherein said means includes apair of wheels mounted to rotate in a common plane about parallel spacedaxes, said body being mounted in tirelike fashion on one of said wheelsin pinched engagement with the other of said wheels with said passageannularly encircling said one of said wheels, whereby travel of saidorifice relative to the fluid in said passage is effected upon rotationof said wheels.
 3. A braking device in accordance with claim 1 whereinsaid means includes a pair of wheels mounted to rotate in a common planeabout parallel spaced axes, one of said wheels being frictionallyengageable with the object so as to be drivingly rotated thereby, saidbody being mounted in tirelike fashion on one of said wheels in pinchedengagement between said wheels with said passage annularly encirclingsaid one of said wheels, whereby said travel of said orifice is effectedthrough rotation of said wheels.
 4. In a gravity conveyor, snubbermechanism for controlling the speed of an object being conveyed alongthe conveyor, said snubber mechanism comprising, a pair of wheelstructures mounted to rotate in substantially nonslip rolling engagementabout a pair of parallel spaced axes with one of said wheel structuresbeing in intercepting relation to the travel path of movement of theobject being conveyed so as to be rotated upon passage of the object,the other of said wheel structures having an outer tire region offlexible material hollowed to define a dead-end flow passage annularlyencircling said other of said wheel structures and containing entrappedfluid, the distance between said axes being less than the sum of theradii of said wheel structures to effect localized pinching of the tireregion and constriction of a corresponding region of the flow passage toprovide a fluid flow restricting orifice within said passage wherebyrotation of said wheel structures produces travel of said orifice influid throttling relation relative to the fluid in said passage, theresistance of the orifice to through-flow of the entrapped fluid actingin opposition to said rotation to produce braking action by said one ofsaid wheel structures on the object when the object is in contacttherewith and being conveyed along the conveyor.